US2569754A - Air directing device for gun-type fuel oil burners - Google Patents

Description

1951 c. M. GRESSLEY 2,569,754

AIR DIRECTING DEVICE FDR GUN-TYPE FUEL OIL BURNERS Filed May 27, 1949 11 INVENTOR. 5 CBHFKRLE MFKHL N RE LEY 7 7 x25. Q- BY ATTORNEY Patented Oct. 2, 1951 AIR DIBECTING DEVICE FOR GUN-TYPE FUEL OIL BURNE Charles Mahlon Gressleh Allegheny County,

search & Development Company, a corporation of Delaware Harrison Township. assignor to Gulf Be- Pifllbllrh,

Application May 27, 1949, Serial No. 95,769 1 Claim. 158-15) This invention relates to an air directing device for gun type fuel oil burners, and more particularly to a device for attachment to the nozzle end of the air blast tube of a gun type fuel oil burner which is designed to burn atomized fuel.

In the combustion of atomized fuel in gun type fuel burners some means is necessary to provide a supply of air or oxygen to the atomized fuel in order to produce combustion of said fuel. Heretofore the art has resorted to devices which produce a turbulent cone of air around the atomized fuel spray. employed by the prior art in that it causes a more thorough mixing of the air with atomized fuel and a greater penetration by the air of the fuel spray cone.

The principal object of my invention is to provide a device which will produce improved combustion in gun type fuel burners.

A further object is to provide a device for mixing air with the fuel spray, said device requiring no moving parts.

Another object of my invention is to provide a device which will not only direct air to the fuel spray but will also serve to confine the flame and prevent impingement thereof on the combustion chamber walls.

A still further object is to provide an air directing means which will allow the fuel nozzle to keep relatively cool thereby minimizing clogging thereof. Other objects will appear hereinafter.

These objects are accomplished by employing my invention in a fuel burner, said invention comprising a plate having a relatively large central circular orifice, a plurality of rows of smaller orifices surrounding said central orifice and a plurality of elongated peripheral slots located near the outer edge of said plate. The purpose of this plate is to break up the supply of air into a plurality of jets. These jets of air are then mixed with the previously atomized fuel.

In the drawings like characters of reference refer to like elements.

Figure l is a side elevation, partly broken away, of a complete furnace employing a gun type fuel burner and shows the relative location of its various parts including my improved air injector.

Figure 2 is an end elevation of my air direction means when attached to the nozzle end of the air blast tube.

Figure 3 is a sectional view of Figure 2 taken along the line 3-3.

Taking up the drawings in detail, in Figure 1 My device differs from those the numeral I refers to my improved air directing plate, which is located in front of and. spaced apart from atomizing nozzle 2. Atomizing nozzle 2 with its fuel supply tube is located centrally of air blast tube 3. The air blower is denoted by numeral 4 and is located at the rear end of air blast tube 3. Numeral Ii designates the main body of the furnace while numeral 5 refers to the combustion chamber proper.

In Figure 2, numeral I again points out the entire air directing means. Numeral 2 designates the atomizing nozzle and shows its position relative to the large central circular opening 1. Numeral 8 refers to one of the plurality of smaller circular orifices which surround central opening 1, said smaller circular orifices being arranged in rows concentric to circular opening I. Numeral 9 points out one of the equally spaced relatively elongated slots which are located near the periphery of plate I.

In Figure 3, the location of my improved air injecting device I with respect to that of air blast tube 3, and that of atomizing nozzle 2 is clearly brought out. In this figure, numeral Ill designates a sleeve portion attached to the rear face of plate I. Sleeve I I is adapted to engage air blast tube 3. Sleeve ll and attached plate I are held in place by means of screws II and II.

The operation of my device is as follows: the air from blower 4 travels down air blast tube 3 to plate I. The relatively large stream of air is broken up at this point into numerous jets of shapes corresponding to the configuration of the various orifices in the plate.

Since the air stream is more confined by the orifices of the plate than by the air blast tube, the speed of the individual jets is somewhat greater than the speed of the air stream in the air blast tube.

The large blast of air passing through the center hole 1 performs the function of creating an initial supply of oxygen for the combustion of the atomized fuel emerging from the nozzle 2.

In addition this center air blast serves to keep the atomizing nozzle 2 relatively cool and minimizes clogging thereof by reducing the amount of heat reflected on said nozzle 2 from the flame and from the combustion chamber 5.

The smaller orifices, surrounding the large central orifice and exemplified by orifice 8, direct a plurality of high velocity jets of air into the partially burned fuel spray and wash away combustion gases from the unburned fuel, while at the same time furnishing additional oxygen for further combustion.

The peripheral slot like openings exemplified by orifice 8 direct more streams of air which perform th same washing and mixing action as produced by the air jets emitted from the smaller orifices and in addition cause the flame to be confined and prevent impingement thereof on the walls of the combustion chamber 5. These peripheral slots are essential in my invention for the production of optimum results. Tests were carried out using plates both with and without said peripheral slots and substantially improved combustion efiiciency was obtained by the use of the plate having the peripheral slots.

As a modification of my invention, 1 contemplate the use of peripheral slots which are not necessarily equally spaced. As a further modification the large central orifice and the surrounding smaller orifices need not necessarily be circular. Circular orifices are preferred, however, for convenience of manufacture. Furthermore, plate I need not necessarily be fiat. A slight concavity or convexity would produce equally improved results without departing from the spirit of my invention. As a still further modifl cation, I contemplate the use of fastening means other than sleeve l and screws H and I2. Any equivalent means which will perform th fastening function may be used. In addition the plurality of smaller orifices exemplified in the drawing by orifice 8 need not be arranged in rows absolutely concentric to large circular orifice I since slight deviations would produce substantially identical results. I do not intend to be limited to the use of four peripheral slots as illustrated. A plate having six such slots, for' fuel, whether said fuel is powdered or liquid.

The principal. advantage produced by my invention is that of improved combustion efilciency. A further advantage of my device is that it employs no moving parts. Consequently, there are no problems of wear and part replacement. A further advantage of my invention is that it reduces clogging of the atomizing nozzle thereby rendering unnecessary frequent cleaning of the said nozzle.

What I claim is:

In combination with a fuel burner having an airblast tube and a burner nozzle located centrally and axially adjacent the discharge end thereof, an air directing device mounted over the nozzle end of said air blast tube and spaced outwardly from said burner nozzle. said air directing device comprising a plate-like member having a relatively large central opening surrounded by a circular series of widely spaced smaller openings, spaced arcuate slots adjacent the periphery of said member, of a curvature centered on the axis of ,said central opening, and concentric rows of closely spaced smaller openings located radially outward of said circular series of widely spaced openings and between said spaced arcuate slots, in groups alternating with said arcuate slotscircumferentially of said member.

' CHARLES MAHLON GRESSLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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